RESUMEN
The results of the Doppler-shift attenuation method lifetime measurements in partner bands of 128Cs and 132La are presented. Experimental reduced transition probabilities in 128Cs are compared with theoretical calculations done in the frame of the core-quasiparticle coupling model. The electromagnetic properties, energy and spin of levels belonging to the partner bands show that 128Cs is the best known example revealing the chiral symmetry breaking phenomenon.
RESUMEN
Self-consistent solutions for the so-called planar and chiral rotational bands in 132La are obtained for the first time within the Skyrme-Hartree-Fock cranking approach. It is suggested that the chiral rotation cannot exist below a certain critical frequency which under the approximations used is estimated as Planck's omega(crit) approximately 0.5-0.6 MeV. However, the exact values of Planck's omega(crit) may vary, to an extent, depending on the microscopic model used, in particular, through the pairing correlations and/or calculated equilibrium deformations. The existence of the critical frequency is explained in terms of a simple classical model of two gyroscopes coupled to a triaxial rigid body.